diff options
| author | Christoph Hellwig <hch@lst.de> | 2020-08-11 18:33:47 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-08-12 10:57:59 -0700 |
| commit | 3d13f313ce4c34c524ccc37986fe77172f601ff3 (patch) | |
| tree | fd71a87be80c03601ab0e3be425fe45da116b5ba /kernel | |
| parent | 428e2976a5bf7e7f5554286d7a5a33b8147b106a (diff) | |
uaccess: add force_uaccess_{begin,end} helpers
Add helpers to wrap the get_fs/set_fs magic for undoing any damange done
by set_fs(KERNEL_DS). There is no real functional benefit, but this
documents the intent of these calls better, and will allow stubbing the
functions out easily for kernels builds that do not allow address space
overrides in the future.
[hch@lst.de: drop two incorrect hunks, fix a commit log typo]
Link: http://lkml.kernel.org/r/20200714105505.935079-6-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Greentime Hu <green.hu@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Link: http://lkml.kernel.org/r/20200710135706.537715-6-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/callchain.c | 5 | ||||
| -rw-r--r-- | kernel/events/core.c | 5 | ||||
| -rw-r--r-- | kernel/kthread.c | 5 | ||||
| -rw-r--r-- | kernel/stacktrace.c | 5 |
4 files changed, 8 insertions, 12 deletions
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c index c6ce894e4ce94..58cbe357fb2bf 100644 --- a/kernel/events/callchain.c +++ b/kernel/events/callchain.c @@ -217,10 +217,9 @@ get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user, if (add_mark) perf_callchain_store_context(&ctx, PERF_CONTEXT_USER); - fs = get_fs(); - set_fs(USER_DS); + fs = force_uaccess_begin(); perf_callchain_user(&ctx, regs); - set_fs(fs); + force_uaccess_end(fs); } } diff --git a/kernel/events/core.c b/kernel/events/core.c index d1f0a7e5b182a..6961333ebad52 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6453,10 +6453,9 @@ perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size, /* Data. */ sp = perf_user_stack_pointer(regs); - fs = get_fs(); - set_fs(USER_DS); + fs = force_uaccess_begin(); rem = __output_copy_user(handle, (void *) sp, dump_size); - set_fs(fs); + force_uaccess_end(fs); dyn_size = dump_size - rem; perf_output_skip(handle, rem); diff --git a/kernel/kthread.c b/kernel/kthread.c index b2807e7be772d..3edaa380dc7b4 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -1258,8 +1258,7 @@ void kthread_use_mm(struct mm_struct *mm) if (active_mm != mm) mmdrop(active_mm); - to_kthread(tsk)->oldfs = get_fs(); - set_fs(USER_DS); + to_kthread(tsk)->oldfs = force_uaccess_begin(); } EXPORT_SYMBOL_GPL(kthread_use_mm); @@ -1274,7 +1273,7 @@ void kthread_unuse_mm(struct mm_struct *mm) WARN_ON_ONCE(!(tsk->flags & PF_KTHREAD)); WARN_ON_ONCE(!tsk->mm); - set_fs(to_kthread(tsk)->oldfs); + force_uaccess_end(to_kthread(tsk)->oldfs); task_lock(tsk); sync_mm_rss(mm); diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c index 2af66e449aa6a..946f44a9e86af 100644 --- a/kernel/stacktrace.c +++ b/kernel/stacktrace.c @@ -233,10 +233,9 @@ unsigned int stack_trace_save_user(unsigned long *store, unsigned int size) if (current->flags & PF_KTHREAD) return 0; - fs = get_fs(); - set_fs(USER_DS); + fs = force_uaccess_begin(); arch_stack_walk_user(consume_entry, &c, task_pt_regs(current)); - set_fs(fs); + force_uaccess_end(fs); return c.len; } |